On the Valley's west side near Los Banos, something strange is happening this summer in the San Joaquin River -- water.
The river has continued to flow to the Pacific Ocean throughout the first summer after an ambitious restoration effort began, sending a powerful signal about the project's potential for success.
This end of the river has been dry in summer since Friant Dam was finished in the late 1940s.
By the end of 2012, officials are supposed to re-establish salmon runs, which perished after the dam was built. But officials need to learn a lot more about the river, 60 miles of which has not been wet year-round in decades.
In the past six months, federal officials have looked at the river from 9,000 feet above, taking aerial photographs to document vegetation, and from within the water, where floating sediment was sampled. Officials are describing the river so they can closely follow changes as restoration continues.
The research started last fall with water releases from Friant, in accordance with the 2006 river-restoration agreement. In March, the river's dry spots filled in and reconnected with the confluence of the Merced River. From there, the San Joaquin continues to the Sacramento-San Joaquin Delta.
Federal officials and many others say they don't remember the last time the river flowed in mid-August on the west side. Without a freak storm or seepage from underground water, there has been no summer water source since the dam was built.
"It's very unusual to see water in the river at this time of year" east of Los Banos, said federal hydrologist Stephen Lee, who collects data on the river.
Lee and technician Carlos Hernandez were retrieving information Tuesday from ground-water monitoring wells and stream gauges in the river at the Highway 152 bridge, about 20 miles from Los Banos.
The ground-water information helps the U.S. Bureau of Reclamation track how far the water spreads out on the west side's expansive plain and how high the underground water table rises around farm fields right next to the river.
More than 80 wells have been established along the river to track the plume of water that seeps into the ground as the river passes.
If the water is building up too close to the ground's surface, federal officials might have to make some adjustment to slow down the water being released from Friant. Too much seepage would kill crops by swamping their root zones.
Officials are investigating one possible seepage-damage problem, but no others have been reported.
Lee and Hernandez checked the depth of the underground water on both sides of the river. Lee said the wells help officials understand how the river is connected to the surrounding ground-water basins.
To check the stream gauge beneath the Highway 152 bridge, Hernandez donned waders -- water-proof trousers and boots. He didn't really need them for the 6-inch-deep water, but he was following standard procedure.
Far above Hernandez and the river were mud nests of barn swallows pasted on the bottom of the concrete bridge. Insects gathered in swarms near the willow trees, and the water felt warm as it drifted past the bridge.
Hernandez and Lee repaired a broken support wire that secures a data recording device in the stream gauge. Hernandez then installed the recorder.
"It records water temperature and depth hourly," Lee said. "Over time, it will give us a good idea of what's going on at this point in the river."
Bureau of Reclamation officials aren't the only ones gathering information and preparing for salmon restoration, which is only 28 months away. The U.S. Fish and Wildlife Service, the U.S. Geological Survey and a number of state agencies are involved, too.
For instance, Fish and Wildlife is expected to file a federal permit application for the restoration by the end of September, officials said. The National Marine Fisheries Service must sign off on the permit because the salmon are a protected species that migrate to the ocean.
The preparation for salmon also will include barriers in the river at Salt and Mud sloughs to prevent migrating fish from mistakenly turning up those waterways to spawn.
Jason Phillips, restoration program boss for the Bureau of Reclamation, said environmental studies for the barriers will begin later this year.
Phillips added that there will be an increase in the water flow from Friant to simulate conditions for fish migration in early November. It will last 10 days, he said.
For now, the river will continue at a lower flow while government scientists study it. That seems fine with restoration supporters, such as Revive the San Joaquin, a nonprofit activist group based in Fresno.
"We're very pleased to see water in the river again," said executive director Chris Acree.